Turbulence Contrarians

A few months ago I came across an intriguing contrarian theory:

Hydrogravitional-dynamics (HGD) cosmology … predicts … Earth-mass planets fragmented from plasma at 300 Kyr [after the big bang]. Stars promptly formed from mergers of these gas planets, and chemicals C, N, O, Fe etc. were created by the stars and their supernovae. Seeded gas planets reduced the oxides to hot water oceans [at 2 Myr], … [which] hosted the first organic chemistry and the first life, distributed to the 1080 planets of the cosmological big bang by comets. … The dark matter of galaxies is mostly primordial planets in proto globular star cluster clumps, 30,000,000 planets per star (not 8!). (more)

Digging further, I found that these contrarians have related views on the puzzlingly high levels of mixing found in oceans, atmospheres, and stars. For example, some invoke fish swimming to explain otherwise puzzling high levels of ocean water mixing. These turbulence contrarians say that most theorists neglect an important long tail of rare bursts of intense turbulence, each followed by long-lasting “contrails.” These rare bursts not only mix oceans and atmospheres, they also supposedly create a more rapid clumping of matter in the early universe, leading to more earlier nomad planets (not tied to stars), which could then lead to early life and its rapid spread.

I didn’t understand turbulence well enough to judge these theories, so I set it all aside. But over the last few months I’ve noticed many reports about puzzling numbers and locations of planets:

What has puzzled observers and theorists so far is the high proportion of planets — roughly one-third to one-half — that are bigger than Earth but smaller than Neptune. … Furthermore, most of them are in tight orbits around their host star, precisely where the modellers say they shouldn’t be. (more)

Last year, researchers detected about a dozen nomad planets, using a technique called gravitational microlensing, which looks for stars whose light is momentarily refocused by the gravity of passing planets. The research produced evidence that roughly two nomads exist for every typical, so-called main-sequence star in our galaxy. The new study estimates that nomads may be up to 50,000 times more common than that. (more)

This new study was theoretical. It used a best fit power law fit to the distribution of nomad planet microlensing observations to predict ~60 Pluto sized or larger nomad planets per star.  When projected down to the comet scale, this power law actually matches known bounds on comet density. The 95% c.l. upper bound for the power law parameter gives 100,000 such wandering Plutos or larger per star.

I take all this as weak support for something in the direction of these contrarian theories – there are more nomad planets than theorists expected, and some of that may come from neglect of early universe turbulence. But thirty million nomad Plutos per star still seems pretty damn unlikely.

FYI, here is part of an email I sent the authors in mid December, as yet unanswered:

The argument [of yours] I’ve found most persuasive and understandable is presented here: http://arxiv.org/pdf/astro-ph/9904260v1 It says that the usual calculations based on observations suggesting little turbulence in oceans, atmospheres etc. neglect the fact that a tiny fraction of space-time volume where it happens can dominate overall mixing rates. The fact that real mixing seems to be vastly larger does support your claims that rare turbulence is an important contribution to real mixing.

But the argument I most want to evaluate is your claim that planet sized objects formed quickly after the universe first turned transparent to light. That seems to be based on a claim that there are gravity instability modes where density increases locally yet pressure remains constant across space. A little searching finds papers like this: http://dx.doi.org/10.1016/j.physleta.2007.09.069 that do explicit perturbation analysis yet don’t find such modes. Computer simulations also don’t seem to find them. Your response seems to be that these neglect non-linearities and the complexity of turbulence. Yet the arguments you give, at least the ones that I have found, such as in http://arxiv.org/pdf/astro-ph/0610628v1 , seem to be simple perturbation arguments. I keep wondering: what complexity-respecting theory are they perturbations of?

Somehow you seem to be postulating a small fraction of turbulence at the transparency transition that had very disproportionate effects in promoting gravitational instabilities. You have in mind some model of the average changes under rare turbulence that support unstable constant pressure density fluctuations. Yet most cosmologists don’t see those as possible. So where exactly is your most detailed argument for the existence of such instabilities in a scenario of mild and/or rare turbulence?

I also never got an answer to this one:

This paper: http://pubs.giss.nasa.gov/docs/1993/1993_Goldman_Canuto.pdf
gives the sort of more detailed calculation that I was looking to find in your papers.
How much does your analysis disagree with their analysis?

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